Copper(II) complexes of the fluoroquinolone antimicrobial ciprofloxacin. Synthesis, X-ray structural characterization, and potentiometric study.
ABSTRACT Reaction of the fluoroquinolone antimicrobial ciprofloxacin with copper(II) nitrate in the presence of 2,2'-bipyridine resulted in the isolation of the complex [Cu(cip)(bipy) (Cl)0.7(NO3)0.3] (NO3).2H2O. Reaction of an aqueous solution of ciprofloxacin.HCl and NaCl with CuCl2 at pH 5.0 resulted in the isolation of [Cu(cip)2]Cl2.11H2O. The complex [Cu(cip) (bipy)(Cl)0.7(NO3)0.3] (NO3).2H2O crystallizes in the monoclinic space group P2(1)/n, with a = 13.955(8), b = 14.280(8), c = 14.192(6) A, beta = 93.10(4) degrees, Z = 4 with R = 0.046. The selective broadening of resonances in the 13C NMR spectrum of ciprofloxacin by the addition of Cu2+(aq) was employed to probe metal ion binding sites in the ligand. The protonation constants of norfloxacin and ciprofloxacin, and the formation constants with copper(II), were determined by potentiometric titrations at 25 degrees C. The additions of ciprofloxacin to metal to form ML and ML2 complexes exhibit stepwise formation constants of log K1 6.2(1) and log K2 11.1(3), respectively.
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ABSTRACT: Quinolones are synthetic broad-spectrum antibiotics with good oral absorption and excellent bioavailability. Due to the chemical functions found on their nucleus (a carboxylic acid function at the 3-position, and in most cases a basic piperazinyl ring (or another N-heterocycle) at the 7-position, and a carbonyl oxygen atom at the 4-position) quinolones bind metal ions forming complexes in which they can act as bidentate, as unidentate and as bridging ligand, respectively. In the polymeric complexes in solid state, multiple modes of coordination are simultaneously possible. In strongly acidic conditions, quinolone molecules possessing a basic side nucleus are protonated and appear as cations in the ionic complexes. Interaction with metal ions has some important consequences for the solubility, pharmacokinetics and bioavailability of quinolones, and is also involved in the mechanism of action of these bactericidal agents. Many metal complexes with equal or enhanced antimicrobial activity compared to the parent quinolones were obtained. New strategies in the design of metal complexes of quinolones have led to compounds with anticancer activity. Analytical applications of complexation with metal ions were oriented toward two main directions: determination of quinolones based on complexation with metal ions or, reversely, determination of metal ions based on complexation with quinolones.Molecules 01/2013; 18(9):11153-97. · 2.43 Impact Factor
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ABSTRACT: The structural features of copper(ii), nickel(ii), cobalt(ii) and zinc(ii) complexes with the antimicrobial drugs quinolones and non-steroidal anti-inflammatory drugs (NSAIDs) as ligands are discussed. The binding properties of these complexes to biomolecules (calf-thymus DNA, bovine or human serum albumin) are presented and evaluated. The biological activity (antimicrobial, antioxidant and antiproliferative) of selected complexes is investigated. Further perspectives concerning the synthesis and the biological activity of novel complexes with quinolones or NSAIDs attractive to synthetic chemists, biochemists and/or biologists are presented.Dalton Transactions 03/2013; · 3.81 Impact Factor
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ABSTRACT: Emerging contaminant ciprofloxacin (CIP) has been frequently detected in soils. Its interactions with metals in soils remain largely unknown. We examined the effects of metal cations Cu and Ca and surface Fe/Al coating on CIP sorption by preloading Cu and Ca onto sand surface or mixing them with CIP in solution. Batch experiments with sand before and after removing Fe/Al coating on surface (coated and clean sand) were used. Based on Langmuir model and compared to clean sand, coated sand not only sorbed 10 times more CIP (50mgkg(-1)) but also with 6 times stronger binding strength (1.95L/μg). Though coated sand had limited Fe and Al on surface (157 and 904mgkg(-1)), they were the major sites for CIP sorption probably via complexation with CIP's carboxyl group. Surface Fe/Al also played an important role in CIP sorption via Cu and Ca cation bridging as evidenced by increased CIP sorption with increasing Cu and Ca concentration preloaded onto sand surface. Different from Cu and Ca on the sand surface, Cu and Ca in solution decreased CIP sorption. Our results suggested that cations in soils could either facilitate or impede CIP sorption depending on they are on solid or solution phase.Journal of hazardous materials 03/2013; 252-253C:375-381. · 4.14 Impact Factor